Photoluminescence Studies Research Articles

Optical, electrical and thermal investigations on brucinium di-hydrogen citrate tri-hydrate single crystal: An optimistic tool for microelectronics, OPO and OLED applications

Highly capable nonlinear optical brucinium di-hydrogen citrate tri-hydrate (BDHCTH) single crystal under organic material category has been grown-up successfully by slow evaporation method. Optical, electrical, and thermal investigations were made on title crystal to discover the suitability of fabrication of an optical as well as electrical device for the first time. Crystal structure analysis confirms that, the BDHCTH crystal belongs to triclinic crystal system with non-centro symmetric space group P1. The SLDT value of BDHCTH crystal was found to be 4.22 GW/cm2. Second harmonic generation efficiency of the BDHCTH compound is 1.08 times superior to the reference sample KDP. An attribution of single and sharp peak with lesser full width half maximum value confirms the presence of very fewer defects in the grown crystal. An electric response of the title compound shows the normal dielectric behavior. The piezoelectric charge co-efficient (d33) was found to be 4.5 p C/N. Photo luminescence study confirms that the synthesized sample possess violet, blue and red emission behaviors. Presences of various functional groups in the title sample were identified by FT-IR study. Thermal stability of the compound BDHCTH was found to be 135 °C. Kinetic parameters such as activation energy, Arrhenius factor, standard entropy of activation, standard enthalpy of activation, standard Gibb's energy of activation (ΔG*) and induction time of the grown sample were found to be 161.6396 k J mol−1, 7.4854 s−1, -230.8278 J K mol−1, 154.854 k J mol−1, 249.0314 k J mol−1 and 52 days respectively. At the end of an optical, electrical and thermal analysis, we concluded that the grown crystal is an optimistic tool for microelectronics, OPO and OLED applications due to existence of good SHG value, lesser defect and red emission behavior.

Entropy-driven nonequilibrium phonon-stimulated electron-phonon coupling in tin dioxide nanorods.

Nonequilibrium (NEQ) phonon fluctuation in a nanosystem has been studied through the statistical assessment of the entropy-production and -consumption events in ultrasmall tin dioxide (SnO_{2}) nanorods. Size- and shape-dependent alteration in free energy leading to modulation of the probability distribution function of the phonon dynamics has been observed from the x-ray diffraction and Raman scattering characterizations. The Gallavotti-Cohen nonequilibrium fluctuation theorem has been utilized to qualitatively describe the aforementioned behaviors under the influence of a global flux. The observation of entropy consumption and thermodynamically favorable entropy-production events indicates the presence of NEQ fluctuations in the phonon modes. The effective energy scale of fluctuation in driven phonon modes, dissipating energy faster than relaxation time, is quantified on the order of nanojoules. From optical absorption and photoluminescence studies, the observation of the electron-phonon coupled state confirms the interaction of the NEQ phonons with electrons. The strength of the coupling has been estimated from the temperature-independent Barry center shift and found to be enhanced to 5.35. Valence band x-ray photoelectron spectroscopy and Fourier transformed infrared spectroscopy analyses reconcile NEQ phonon mediated alteration of the valence band density of states, activation of silent phonon modes, and superior excitonic transitions, suitable for the new generation of ultrafast quantum device applications.

Probing nonlinear excitation conditions: photoluminescence and nonlinear absorption studies in laser-irradiated dielectrics

Understanding the fundamentals of laser-matter interactions is crucial for developing and optimizing ultrafast laser processing strategies. In optically transparent solids, the key event by which energy is deposited in the material is through the generation of an electron–hole plasma via nonlinear excitation mechanisms. As the energy stored in the plasma relaxes, local distortions of the lattice may occur, such as point defects. These defects give rise to new discrete energy states located in the bandgap. In this study, we investigate how the presence of these energy states influences the transmission of ultrashort near-infrared laser pulses in fused silica. Experimental results of laser pulse transmission and photoluminescence from defects are correlated with optical microscopy of the irradiated spots, allowing us to identify different nonlinear interaction regimes. Numerical simulations indicate that photo-induced defects influence the nonlinear losses of ultrashort laser pulses and explain why a non-destructive damage regime with detectable excitation is only observed for a narrow intensity range in multipulse experiments.

Colour-tunable features in thermally stable Tb3+/Eu3+ co-doped telluro tungstate glasses for photonic applications

The melt quenching procedure has been followed to synthesize transparent Tb3+ singly activated and Tb3+/Eu3+ co-activated TeO2–WO3–K2O–ZnO–Bi2O3 (TWKZBi) glasses. The structural characteristics of the prepared TWKZBi glass samples were examined through x-ray diffraction. The existence of functional units corresponding to the different vibrations has been examined via Raman spectroscopy. The photoluminescent characteristics and energy transfer (ET) analysis in the Tb3+/Eu3+ co-activated TWKZBi glasses were investigated in depth. Several emission peaks have been observed in Tb3+ doped TWKZBi glasses under n-UV and blue excitations and the maximum luminescent intensity has been detected for 2.0 mol% of Tb3+ doped TWKZBi glass sample. The emission spectra of co-doped Tb3+ and Eu3+ ions in the TWKZBi glasses have been studied, and the maximum ET efficiency is found to be 32.82% under n-UV excitation. The ET from sensitizer (Tb3+) to activator (Eu3+) ions happen through dipole–dipole interaction, as confirmed by Dexter’s and Reisfeld’s approximation. The colour-tunable emission in the prepared glass samples can be achieved via varying the content of activator ions. The decay profiles for the 5D4 level of Tb3+ ions diminish with varying the concentration of Eu3+ ions, confirming the ET from Tb3+ to Eu3+ ions. Furthermore, temperature-dependent photoluminescence studies show that the Tb3+/Eu3+ co-doped TWKZBi glasses have good thermal stability. All the aforementioned results reveal the suitability of the Tb3+/Eu3+ co-activated TWKZBi glass samples for photonic applications.

Photoluminescence and photocatalytic degradation studies of Zn-based nanoparticles on malachite green dye

Water, the most fundamental source of life, is contaminated by various organic pollutants, especially organic dyes from the dying industry. The photocatalytic degradation of malachite green (MG) was studied using a zinc-based metal-organic framework (Zn-BTC MOF) and ZnO. Thermally decomposing Zn-MOF synthesized ZnO and its structural and optical properties were analyzed using various spectroscopic techniques. This article focuses primarily on the wavelength-dependent photoluminescence properties of Zn-MOF and ZnO materials and their role in the photocatalytic degradation of MG dye in water. Zn-MOF and ZnO photocatalysts exhibited a photodegradation efficiency of approximately 99% after 40 min of visible light exposure. Based on kinetic experiments, the degrading efficiency of these catalysts followed pseudo-first-order reaction kinetics with a correlation of R2 = 0.99 and a rate constant of 0.031 min−1. This manuscript is helpful to researchers working on ZnO and Zn-MOF materials for photocatalytic and environmental applications.

Photoluminescence of Erbium-Doped ZnO Nanostructures

The present work reviews the results of the photoluminescence study of erbium-doped ZnO nanostructures synthesized by physical and chemical methods. ZnO is a semiconductor compound composed of zinc and oxygen atoms. It possesses a wide bandgap (3.37 eV) and is optically and electrically active. When ZnO is synthesized in the form of nanostructures, such as nanoparticles, nanowires, nanorods, nanotubes, or nanosheets, it exhibits enhanced properties compared to its bulk counterpart due to quantum confinement effects and a high surface-to-volume ratio. By controlling different parameters in the growth processes of erbium-doped ZnO nanostructures, materials can be synthesized for different applications such as sensors, optoelectronics, and energy harvesting.

Significant transformation in the point defects evidenced via theoretical simulations supported by Raman and photoluminescence studies in vertically grown 1D ZnO nanorods triggered by titanium ion implantation

One-dimensional ZnO exhibits fascinating electrical and optical properties enabling remarkable performance in photonics, sensors, optics and photovoltaic devices. Stopping and Range of Ions in Matter (SRIM) simulations for Ti ion implantation into ZnO nanorods (NRs) at varying fluences (1 × 1014 to 5 × 1015 ions/cm2) at 100 keV results in an electron to nuclear energy loss ratio (Se/Sn) of 0.22, with maximum Ti ion occurrence and point defects within 100 nm along the NRs. Theoretical predictions align with experimental results especially of Raman scattering, X-ray photoelectron spectroscopy, and photoluminescence confirming an increase in the structural point defects with escalating Ti fluence. The pristine ZnO NRs initially exhibit yellow-orange photoluminescence emission. Following implantation, this emission transforms into green, which is due to zinc vacancies. The agreement between theoretical simulations and experimental results affirms the validity of our investigation into the formation and progression of point defects in Ti-implanted ZnO NRs.

A Stimuli-Responsive Dual-Emitting Covalent Organic Framework Shows Selective Sensing of Highly Corrosive Acidic Media via Fluorescence Turn-On Signal with White Light Emission.

Luminescent covalent organic frameworks (LCOFs) have been employed as platforms for sensing analytes. Judicial incorporation of appropriate functional units inside the framework leads to the different electronic states in the presence of external stimuli, e.g., temperature, pH, etc. We report herein a new COF (TPEPy) as a solid-state acid sensor specific for the highly acidic environments that range from pH ∼0.5 to ∼3.0. This COF shows a protonation-induced reversible color change from bright yellow to deep red upon decreasing the pH from 3 to 0.5 and vice versa. No visual color change was, however, observed above pH 3.0. Photoluminescence (PL) studies show that the intrinsic emission peak of the TPEPy COF at 530 nm is shifted to 420 nm owing to the N-protonation of the imine nitrogen of COF within this pH range. Extensive studies demonstrate that the protonation behavior of the COF is counterion dependent. This was revealed when different acids, e.g., HCl, HNO3, HBr, and HI, were employed. The intensity of the proton-induced emission peak at 420 nm depends significantly upon the counterions with the order of HCl > HNO3 > HBr > HI. These anions interact with the protonated TPEPy COF by cation-anion and H-bonding interactions. Further, the pristine COF showed near white light emission at a particular pH of 2.5 (CIE coordinates 0.27, 0.32). From the PL spectrophotometric titrations, the deprotonation pKa was experimentally found to be 1.8 ± 0.02 for the TPEPy COF. The sensor reported herein is reversible, reusable, and regenerable and is useful for assessing pH fluctuations within a strongly acidic range via digital signaling.

First Eu3+, Gd3+ and Tb3+ complexes containing the non-steroidal anti-inflammatory drug ketoprofen and N,N-donors ligands: Synthesis, solid state characterization and photoluminescence studies

Reports on lanthanide complexes derived from non-steroidal anti-inflammatory drug molecules are still quite scarce in the literature, despite the potential properties of these molecules as therapeutic agents and biological markers. The current literature reports only lanthanide compounds containing the ketoprofenate ligand, most of the time containing coordination water molecules, which causes serious luminescence suppression. This study reports three new classes of highly photoluminescent lanthanide ketoprofenates with general formulas [Ln2(keto)6(bpy)2] (1)–(3), [Ln2(keto)6(phen)2] (4)–(6) and [Ln2(keto)6(4,4′-dmbpy)2] (7)–(9) (where: Ln = Eu3+, Gd3+ e Tb3+; keto = ketoprofenate anion, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline and 4,4′-dmbpy = 4,4′-dimethyl-2,2′-bipyridine). These nine complexes were fully characterized and the photophysical studies were carried out in detail. Furthermore, the energy transfer mechanism was completely elucidated with the aid of theoretical calculations using the Sparkle/RM1 method, closely related to the nature of the employed ancillary ligand. The calculated luminescence spectroscopic parameters are in excellent agreement with those obtained experimentally, reinforcing the homobimetallic structure for these complexes. With the highest values of quantum efficiencies ( %η) ever reported for lanthanide ketoprofenates, these compounds comprise potential molecules for use as biological markers or anti-inflammatory agents.

Bridging two worlds: (DABCO-H)CuKI3 a hybrid copper iodide phosphor with a perovskite structure

Abstract A novel copper iodide hybrid compound, (DABCO-H)CuKI3, featuring a perovskite structure is here reported. Characterization techniques, including single crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and photoluminescence studies, elucidate the structural and luminescent properties. The compound exhibits blue phosphorescence, attributed to mixed metal-to-ligand and halide-to-ligand charge transfer transitions, as supported by density functional theory (DFT) calculations and XPS valence band analysis. Furthermore, (DABCO-H)CuKI3 displays a remarkable adsorption capacity towards methylene blue dye. Kinetic modelling reveals that both film and intra-particle diffusion processes contribute to the adsorption rate.

Amine‐Free Multi‐Faceted CsPbBr3 Nanocrystals for Complete Suppression of Long‐Lived Dark States

AbstractConventional amine‐capped perovskite nanocrystals (A‐PNCs) often show microscopic fluctuation (blinking) of photoluminescence (PL) between bright and near‐background (dark) states. The transient dark phases spanning milliseconds (ms) to several seconds timescale typically owe to the non‐radiative (NR) fate of charge carriers in crystal defect states, limiting the PNC's efficiency in optoelectronics. A PL study of a novel trioctylphosphine (TOP) capped rhombic cuboctahedron‐shaped amine‐free (AF) PNC is presented, demonstrating their fascinating nonblinking nature. While oleylamine‐capped hexahedron A‐PNCs as a reference system show long dark states, their population is completely suppressed in ≈90% of AF‐PNCs with random large‐amplitude PL fluctuations several times above the background. The PL trajectories of AF‐PNCs primarily comprise constant power spectral densities (PSDs) which are unprecedented and deviate from power‐law distribution as observed for A‐PNCs and most of the other blinking nanocrystals. Such signature of PSDs and frame‐by‐frame intensity jump analysis indicate a fast (<<ms) timescale charge‐carrier dynamics governing the PL emission of AF‐PNCs, likely involving short‐lived metastable states. Besides, long‐term stability and suppressed dark phases in ≈70% AF‐PNCs even 90 days after the synthesis is noteworthy. Altogether the study provides exceptional optical characteristics of photostable amine‐free PNCs which would be attractive to exploit in commercial display applications.

Utilizing the lignocellulosic fibers from Pineapple Crown Leaves extract for enhancing TiO2 interfacial bonding in dye-sensitized solar cell photoanodes

AbstractThe crown leaves of pineapple possess a wealth of smooth and glossy silk medium-length fibers, primarily composed of cellulose and lignin, accompanied by constituents such as fats, waxes, pectin, uronic acid, anhydride, pentosan, color pigments, and inorganic substances. These fibers exhibit an anisotropic nature and are characterized by hydrogen bonding interactions, rendering them effective in conjunction with semiconductor oxide (TiO2) through their cellulosic fibrils. The dye extracted from Pineapple Crown Leaves (PCL) using ethanol was subjected to FTIR and UV–visible spectroscopy. The FTIR analysis revealed absorption peaks at 3268 cm−1 and 2922 cm−1, confirming the presence of –OH and –CH stretching attributed to the fibrils within the dye. UV–visible spectroscopy further demonstrated absorption within the visible region of the electromagnetic spectrum. Additionally, a photoluminescence study of the dye showcased emission within the visible range of the electromagnetic spectrum. Subsequently, a solar cell incorporating this dye underwent JV characterization, yielding an efficiency of 1.0034%, along with fill factor, open-circuit voltage, and short-circuit current density values of 0.40644, 0.7058 V, and 3.4906 mA/cm2, respectively. To gain deeper insights and facilitate optimization for large-scale installations, a simulation model utilizing PC1D was proposed to explore the influential parameters of the Dye-sensitized solar cell (DSSC).

Unveiling the Ultrafast Electron Transfer Dynamics in Epitaxial Dodecahedron CsPbBr3/Au Heterostructure

AbstractEpitaxial perovskite heterostructures consisting noble metal nanoparticles have been received immense interest in hot carrier photovoltaic devices and photocatalysis. The major understanding of carrier extraction across the interface of perovskite heterostructure have shown exciting interest for next generation device applications. In the present study, dodecahedron CsPbBr3/Au heterostructure was synthesized via hot injection method. From HR‐TEM images, we observed direct epitaxial growth between (110) plane of CsPbBr3 and (111) plane of Au nanoparticle (NPs), which was further supported by steady‐state and time‐resolved photoluminescence studies. Further, femtosecond transient absorption spectroscopy has been utilized to understand the charge transfer dynamics of synthesized samples. In CsPbBr3/Au heterostructure, faster recovery has been noticed than that of pristine CsPbBr3, which clearly suggests transfer of electrons from the conduction band of CsPbBr3 to Au NPs. The distinct fast electron transfer in the CsPbBr3/Au heterostructure can be mainly ascribed to the epitaxial growth and strong electronic coupling between CsPbBr3 and Au NPs. The reduced bleach intensity, faster bleach growth and recovery kinetics strongly suggest efficient electron transfer from CsPbBr3 NCs to Au NPs. These findings clearly establish that architecture of metal and perovskite heterostructures may pave way to develop suitable alternative for highly efficient photovoltaic devices and photocatalysis applications.

Highly sensitive optical approach towards Cu (II) ions detection in water sample using thioglycolic acid capped vanadium disulfide-based dichalcogenide quantum dots

Copper-dependent enzymes play an important role in the biological functions of the human body, plants, various micro/macro-organisms and animals. However, extensive and excessive consumption of Cu leads to damage of DNA strands, irregulating antioxidant enzyme function, brain damage, and other acute diseases like fever, nausea, headache, vomiting, diarrhea, etc. Herein, we synthesized water-soluble thioglycolic acid (TGA) capped vanadium disulfide-based dichalcogenide quantum dots (TGA@VS2 QDs) via a facile hydrothermal method. TGA acts as the sulfur source and capping group to making QDs water-soluble. Apart from this, TGA also provides high stability to QDs by preventing agglomeration as well as improving biocompatibility properties. The present study has proposed the interaction of TGA@VS2 QDs with environmental pollutant metal ions Zn (II), Pd (II), Fe (III), Cu (II), K (I), Cr (VI), Cd (II), and Ca (II) in the aqueous solution through photoluminescence (PL) spectroscopy. PL study showed specific interaction towards Cu (II) using TGA@VS2 QDs. The response study was carried out in two concentrations range from 10−8 M – 10−3 M in two parts from 10−8 M – 10−5 M & 10−5 M – 10−3 M and observed the linear decrease of PL intensity. While other metal ions Zn (II), Pb (II), Fe (III), K (I), Cr (VI), Cd (II), and Ca (II) did not show a quenching process with TGA@VS2 QDs. The quenching process involved is the static in nature for Cu (II) and it was confirmed by UV–visible, PL studies and Time-correlated single-photon counting (TCSPC) with a limit of detection 50 nM.

Exciton localization and dynamics in GaNAsP nanowires

This work investigates exciton localization and dynamics in semiconductor GaNAsP nanowires (NWs) with varying nitrogen concentrations. Through detailed time-resolved photoluminescence studies, we identify a nitrogen composition-dependent difference in exciton transfer between localized states formed due to alloy disorder. With [N] = 0.1%, the localized states exhibit cluster-like, non-interacting behavior, whereas at [N] = 1.1%, a continuous band of localized states is observed. Additionally, the phosphorous incorporation in the NWs appears to enhance the exciton spatial confinement compared to behaviors observed in phosphorous-free GaNAs NWs, emphasizing the role of the alloy composition in the nature of exciton localization. Temperature is highlighted as a significant factor affecting exciton mobility, enabling efficient transfer between the localized states at higher temperatures. This, in turn, influences exciton lifetimes. Our findings, therefore, shed light on the nature of exciton dynamics in GaNAsP NWs, enriching our understanding of these materials and paving the way for their applications in optoelectronics.

Preparation, Crystal Structure, Physico‐chemical and Nonlinear Optical Properties of a New D‐π‐A Centrosymmetric Stilbazolium Framework of 4‐[2‐(3hydroxy‐phenyl)‐vinyl]‐1‐methyl‐pyridinium iodide (HMPI)

AbstractNew organic Stilbazolium cation Salt of 4‐[2‐(3 hydroxy‐phenyl)‐vinyl]‐1‐methyl‐pyridinium iodide (HMPI), which was obtained through solvent evaporation solution growth. The crystal structure was proved via the SC‐XRD technique. Its outcome reveals that the HMPI crystallised in a centrosymmetric pattern (P121/n1) and monoclinic crystal system. The compositional analysis was performed via 1H NMR and 13C NMR. The FT‐IR spectrum was used to determine the vibrational mode of the different molecular groups present in the material. The intermolecular interactions in the crystal structure were studied using Hirshfeld surface analysis. The molecular orbital energies (HOMO‐LUMO) and molecular electrostatic potential (MESP) were estimated using the Gaussian program with the density functional theory (DFT) method. The linear optical study revealed the transmittance percentage, lower cut‐off wavelength, and energy band gap for HMPI crystal. In the photoluminescence study, a green colour broad emission peak is observed at 521 nm. TG and DTA measured the thermal behaviour of grown HMPI crystal. Chemical etching and atomic force microscopy (AFM) experiments were used to report the surface properties of grown HMPI crystal. The Z‐scan technique, a He−Ne continuous wave laser at 632.8 nm used to measure the third‐order nonlinear optical susceptibility of the HMPI crystal. The Z scan approach reveals a saturable absorption and self‐defocusing nature of the title crystal.

Structural and optical properties of silicon oxycarbide thin films using silane based precursors via sol-gel process

Silicon oxycarbide (SiCxOy) is a candidate material for white luminescence. This work investigates the formation of SiCxOy thin film coating by sol-gel route using various silanes namely, methyltrimethoxy silane (MTMS) with or without using tetraethyl orthosilicate, vinyltrimethoxysilane and polydimethyl siloxane, followed by calcination at 1000 °C/1 h under Ar atmosphere. The structural and optical properties of the developed films were studied by X-ray diffractomete (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), electron paramagnetic resonance (EPR) spectroscopy and Photoluminescence (PL). XRD plot shows amorphous nature of silicon oxycarbide (SiCxOy) while FTIR reveals Si-C band at 795 cm−1 and Si-O-Si band at 1085 cm−1 confirming the presence of SiCxOy. XPS analysis of MTMS derived coating revealed stoichiometry of SiC0.3O2.25 which is comparable to SiCxOy (0.2<x<0.6, y<1.6). EPR spectra analysis shows presence of Si-dangling bond which could be the probable cause of luminescence center in SiCxOy as observed from PL study. FESEM shows uniform coating of thickness ∼200 nm. PL spectra shows blue and green emission peaks at ∼ 403–452 and ∼ 483–560 nm, respectively.

Excited state absorption induced optical limiting behavior of pure, single, and co-doped copper oxide nanoparticles

Underneath nano pulsed green laser (Nd: YAG), nonlinear absorption and optical limiting behavior were analyzed using Z-scan technique for pure CuO, Ag, and Mn-doped CuO (single dopant), and Ag/Mn-doped CuO (co-dopant) nanoparticles intermediated from M. Oleifera leaf extract. X-ray diffraction pattern confirmed that the synthesized nanoparticles were in good crystalline nature with a monoclinic phase and the average crystallite size was estimated in the range of nanometer. FE-SEM analysis displayed that the pure CuO, Ag-doped CuO, and Ag/Mn-doped CuO appear as nanospheres whereas Mn-doped CuO forms themselves as nanorods. The existence of Cu, O, Ag, and Mn elements in synthesized nanoparticles was affirmed by an EDAX spectrum. FT-IR analysis confirms the presence of functional groups. In zeta potential analysis the negative (-ve) potential values −34.23 mV to −34.80 mV indicate the stability of the nanoparticles. The optical study revealed that the nanoparticles possess absorbance maxima in the UV region between 260 nm to 294 nm. The occurrence of a single ionized oxygen vacancy defect was affirmed by the photoluminescence studies. Z-scan studies with nano pulsed Nd: YAG lasers show all the samples exhibit two-photon absorption (2 PA) and optical limiting behavior. In contrast with pure and co-dopant materials (Ag/Mn-doped CuO), the dominant nonlinear absorption coefficients (0.90 × 10−10 m/W, & 0.98 × 10−10 m/W) and submissive values of optical limiting threshold (1.69 × 1012 W/m2 & 1.31 × 1012 W/m2) were found for single dopant materials (Ag & Mn-doped CuO). Thus single metal doped CuO finds potential application in the creation of laser safety devices against massive power nano pulsed green laser beams.

Green Synthesis of Er-Doped ZnO Nanoparticles: An Investigation on the Methylene Blue, Eosin, and Ibuprofen Removal by Photodegradation.

We present a study on the green synthesis of undoped and Er-doped ZnO compounds using Mangifera indica gum (MI). A set of tests were conducted to assess the structure of the material. The tests included X-ray diffraction, Raman, and Fourier-transform infrared spectroscopy. Optical properties were studied using diffuse reflectance and photoluminescence. Morphological and textural investigations were done using SEM images and N2 adsorption/desorption. Furthermore, photocatalytic tests were performed with methylene blue (MB), yellow eosin (EY), and the pharmaceutical drug ibuprofen (IBU) under UV irradiation. The study demonstrated that replacing the stabilizing agent with Mangifera indica gum is an effective method for obtaining ZnO nanoparticles. Additionally, the energy gap of the nanoparticles exhibits a slight reduction in value. Photoluminescence studies showed the presence of zinc vacancies and other defects in both samples. In the photocatalytic test, the sample containing Er3+ exhibited a degradation of 99.7% for methylene blue, 81.2% for yellow eosin, and 52.3% for ibuprofen over 120 min. In the presence of methyl alcohol, the degradation of MB and EY dyes is 16.7% and 55.7%, respectively. This suggests that hydroxyl radicals are responsible for the direct degradation of both dyes. In addition, after the second reuse, the degradation rate for MB was 94.08%, and for EY, it was 82.35%. For the third reuse, the degradation rate for MB was 97.15%, and for EY, it was 17%. These results indicate the significant potential of the new semiconductor in environmental remediation applications from an ecological synthesis.

Nucleation kinetics, chemical etching, hirshfeld surface, and photoluminescence of Rubidium hydrogen oxalate dihydrate NLO single crystal

The nucleation dynamics of a semi-organic Rubidium hydrogen oxalate dihydrate (RbHOH) crystal were assessed using double-distilled water as a solvent medium to obtain good quality crystal using the solution growth technique. Gravimetric analysis of solubility revealed that it has a positive temperature coefficient of solubility, which is appropriate for bulk growth. Other nucleation parameters such as metastable zonewidth, induction period, and interfacial energy were carried out using the classical theory of nucleation. The photoconductivity experiments reveal that the grown crystal exhibits a positive photoconductivity nature. Chemical etching and atomic force microscopy (AFM) experiments were performed on the produced crystal surface. From AFM experiments, effectively assessed amplitude parameters were calculated. Etching studies showed the presence of etch pit patterns such as tiny hillocks and rectangular shapes. Intermolecular interactions were analysed by using Hirshfeld surface analysis. In the photoluminescence (PL) studies, the grown crystal indicates green emission peaks at 519 nm, and the bandgap energy is found to be 4.8 eV. At room temperature, the refractive index of the RbHOH crystal was determined to be 1.669. The nonlinear optical (NLO) efficiency of the grown crystal was examined using a second harmonic generation efficiency test, and it was determined to be 0.58 times that of KDP.